Like sumo wrestlers, samurai, shogun, and other Japanese archetypes, ninja are known outside Japan mostly by exaggerated and often fictionalized characteristics. The exaggerations include their black hooded uniforms and superhuman abilities like walking on water or scaling vertical walls. Ninja have been made even more cartoonish because of the popularity of the comic book and animation series Teenage Mutant Ninja Turtles. John Man helps rectify the misunderstandings about ninja, which is not an easy task as their origins and practices are in the shadows of Japanese history.

The term ninja comes from the concept of “one who endures or hides” which emphasizes the main principles of the ninja. Their main task was spying on the enemy by infiltrating their defenses using techniques learned in the practice of ninjutsu. The techniques including hiding where they could gather intelligence or disrupt enemy plans. And to bring back the information they discovered they must endure; in other words they were not on suicide missions.

The origins of ninja are murky and go back to China more than a thousand years ago as do many Japanese arts. But the height of the ninja influence was during the constant civil wars from about 1480 to 1600 (called the Age of Warring States), and this is where Man focuses much of the book. The battles for territorial dominance by powerful families, was centered around the capital of Kyoto where the emperor resided. The main ninja training centers arose in the nearby regions then known as Iga and K¬ōga. Much of the historical record of the ninja from this time were attributed (although somewhat uncertainly) to a samurai and ninja named Natori Masatake.

Ninja were trained in many aspects of infiltration and martial arts, but also in medicine, psychology, religion, philosophy, among other subjects. These fundamentals provided the ninja with alternate ways of accomplishing their mission. Instead of donning a black uniform and scaling a castle wall, a ninja might use deception or charm to get inside. One ninja mantra was “A well trained ninja looks like a very stupid man”. Ninja rarely carried obvious weaponry, not like the samurai with their long and short swords, and protective armor. Instead Natori recommended a straw hat, a thin rope and grappling iron, a pencil, basic medicine, a long piece of cloth, and a fire starter. Rather than all black clothing, ninja were instructed to wear the colors of the locals to blend in with them.

Not that the ninja weren’t also trained to defend themselves or kill when necessary. If they needed to kill, they often used a dagger easily concealed to be used in a surprise attack. They were also trained to use ordinary tools such as shovels for weapons. Ninja training combined the physical and mental similar to the rigorous mountain training called Shugendō. But even this training was less about mindless killing than about self-improvement. Man describes the often heroic exploits and contributions of the ninja in the most detail in the chapters about the great battles of the Age of Warring States. These battles were as bloody and often ludicrous as any wars in human history. By the mid-sixteenth century, the ninja were in demand across Japan.

After the end of the wars around 1600, Japan was unified by an all-powerful shogun, and the ninja became less important. There were ninja schools that continued their training, and even one or two continue to today. But the samurai maintained order and protected their lords instead of the mercenary ninja. After the end of the shogun rule and return of power to the emperor and the rise of new militarism, some of the ninja principles and techniques were adopted to modern warfare, especially for intelligence gathering during the Asian theater of the Second World War. Man makes the case that the last ninja (although there are several to claim that title) is Hiroo Onoda, a Japanese soldier in the Philippines who did not surrender after the end of the war. He finally gave up in 1974, after avoiding capture and efforts to lure him from the jungles where he survived ninja-like for thirty years.

John Man’s book isn’t all historical accounts; he also explores the sites where ninja influenced the outcomes of battles. He visits a ninja museum, a ninja-themed restaurant, and takes part in ninja training. There are also descriptions of ninja in popular culture and several pages of photos are also included. Overall, the book is a fascinating and highly readable account of the shadowy and misunderstood warriors that helped lay the foundation for modern Japan.